An experimental pilotless plane has broken the world speed record for an atmospheric engine, briefly flying at 7,700 kilometres per hour – seven times the speed of sound, NASA says.

The SCRAMjet program is an attempt to find a replacement the Space Shuttle. The air-breathing supersonic engine is NASA’s prime candidate for the next generation of smaller, lighter, and much more efficient reusable space vehicles. The technology has the potential to revolutionize space travel, but the program is still in its infancy, and faces significant technical challenges such as sustaining thrust at hypersonic speeds and developing a composite replacement for the space shuttle’s “tiles.” Given the nature of NASA’s bureaucracy, I think it’s more likely that an intermediate Shuttle-era replacement will be developed in the meantime. Meanwhile, several X-Prize teams plan to use a variations of a supersonic-combustion ramjet engine. My bet for the next-generation spacecraft is Burt Rutan.